Varicose veins are blood vessels that have become enlarged and tortuous over a period of time. Most commonly, varicose veins occur in veins on the leg, although they can occur elsewhere. Varicose veins are caused when the leaflets of the valves in the blood vessel no longer close properly, thereby allowing for retrograde flow and pooling of blood.
Varicose veins are most common in the superficial veins of the legs. They are often painful and can produce ankle swelling, skin discoloration, dermatitis or venous eczema, cramps, and skin tightness around the affected region. In severe cases of varicose veins, complications may occur. For example, the varicose veins may become very painful and hinder a person's ability to work or perform routine motions and exercises. Skin conditions including itching and flaking associated with varicose veins may also predispose a person to skin loss. Development of serious conditions like blood clots, carcinoma, or sarcoma, may also occur.
As a result, many non-surgical and surgical treatments of varicose veins have been developed. Non-surgical treatments include sclerotherapy, elastic stockings, elevating the legs, and exercise. The traditional surgical treatment has been vein stripping to remove the affected veins. Newer surgical treatments include ultrasound-guided foam sclerotherapy, radiofrequency ablation and endovenous laser treatment.
Sclerotherapy is a commonly performed non-surgical treatment for treating varicose veins in which a sclerosing agent is injected into the veins to make them shrink. Complications of sclerotherapy are rare but can include blood clots and ulceration. Furthermore, conventional sclerotherapy techniques often result in incomplete and/or uneven treatment along the length of the patient's blood vessel.
In order for sclerotherapy to be effective, it is necessary to evenly dispense the sclerosing agent throughout the wall of the vein without using toxic levels of the sclerosing agent. This is not particularly difficult for the smaller veins. However, it is quite difficult or nearly impossible in larger veins. When a larger vein is injected with a sclerosing agent, the sclerosing agent is quickly diluted by the large volume of blood in the vein. As a result, the vein is sclerosed only in the region of the injection. If the procedure is continued, and the injections are far apart, the vein can become disfigured. The problem cannot be cured by injecting a more potent solution of sclerosing agent, because the sclerosing agent may become toxic at such a concentration. Therefore, a need exists for a system that is capable of delivering a sclerosing agent to the varicose vein walls that prevents the dilution of the sclerosing agent into the blood.